Interpretive Summary: There is concern that supplies of pine bark (PB), the industry standard for container plant production, may become limited creating a need for alternative substrates. Alternative substrates have been used to grow containerized ornamentals; however, before widespread adoption of these materials can take place, landscape performance of plants produced in these substrates needs to be established. This study evaluated the landscape performance of three commonly grown woody ornamentals (crape myrtle, magnolia, and oak) following container production in alternative wood-based substrates [WholeTree (WT) and Clean Chip Residual (CCR)]. Results showed that all species performed similarly following outplanting into the landscape when originally grown in WT or CCR compared to the PB industry standard.

Technical Abstract:
Due to concerns over future pine bark (PB) availability for container plant production, recent research has focused on evaluating suitable alternatives. For alternatives to be considered suitable substrate replacements, they must not only have desirable characteristics as a container substrate (e.g. adequate drainage, inert, pathogen free, etc.), but must also cause no negative fertility effects (e.g., nitrogen immobilization) following landscape outplanting. The study objective was to evaluate the landscape performance of three woody ornamentals grown in PB and in two alternative wood-based substrates: WholeTree (WT) and Clean Chip Residual (CCR). Crape myrtle (Lagerstroemia indica × faurei ‘Acoma’), magnolia (Magnolia grandiflora ‘D.D. Blanchard’), and Shumard oak (Quercus shumardii) were grown in PB, WT, or CCR for an entire growing season prior to being outplanted into the landscape. Plants were grown in the landscape for two growing seasons. Data suggest that all species exhibited similar landscape performance when grown in WT or CCR compared to the PB standard. Therefore, use of WT and CCR as alternative wood-based substrates for crape myrtle, magnolia, and oak production may be acceptable from a landscape establishment standpoint.